Graphene is a substance composed of pure carbon. Its atoms arranged in a regular hexagonal pattern similar to the normal graphite. However, graphene is structurally a one-atom thick sheet. It is very light, with a 1-square-meter sheet weighing only 0.77 milligrams. Graphene is an allotrope of carbon. Its structure is one-atom-thick planar sheets of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. The term graphene was coined as a combination of graphite and the suffix -ene by Hanns-Peter Boehm, who described single-layer carbon foils in 1962. Graphene is most easily visualized as an atomic-scale chicken wire made of carbon atoms and their bonds. The crystalline or “flake” form of graphite consists of many graphene sheets stacked together. In essence, graphene is an isolated atomic plane of graphite. The Nobel Prize in Physics for 2010 was awarded to Andre Geim and Konstantin Novoselov at the University of Manchester “for groundbreaking experiments regarding the two-dimensional material graphene”.
The carbon-carbon bond length in graphene is about 0.142 nanometers. Graphene sheets stack to form graphite with an interplanar spacing of 0.335 nm, which means that a stack of three million sheets would be only one millimeter thick (approximately the thickness of a U.S. dime coin). Graphene is the basic structural element of some carbon allotropes including graphite, charcoal, carbon nanotubes and fullerenes. It can also be considered as an indefinitely large aromatic molecule, the limiting case of the family of flat polycyclic aromatic hydrocarbons.
People are so interested in graphene because of its ground-breaking two-dimensional structure and a number of unique properties. For instances, graphene appears to be one of the strongest materials ever found. Measurements have shown that graphene has a breaking strength over 100 times greater than a hypothetical steel film of the same thickness. It has displayed an anomalous quantum Hall effect with the sequence of steps shifted by 1/2 with respect to the standard sequence; and these remarkable anomalies can even be measured at room temperature, i.e. at roughly 20° C. Graphene also has remarkably high electron mobility at room temperature, which makes it a suitable material for the construction of future quantum computers using anyonic circuit.
Several potential applications for graphene are under development, and many more have been proposed. These include lightweight, thin, flexible, yet durable display screens, electric circuits, and solar cells, as well as various medical, chemical, and industrial processes enhanced or enabled by the use of new graphene materials. For instances, graphene has the ideal properties to be an excellent component of integrated circuits. It has a high carrier mobility, as well as low noise, allowing it to be used as the channel in a field-effect transistor. In addition, graphene's high electrical conductivity and high optical transparency make it a candidate for transparent conducting electrodes, required for such applications as touch screens, liquid crystal displays, organic photovoltaic cells, and organic light-emitting diodes.
Giving its outstanding electrical, mechanical and chemical properties, and great application potentials, the practical technologies about graphene synthesis and transfer is the key for its future applications in various areas. In recent years, the research papers about graphene have been mainly focusing on graphene synthesis, transfer and applications. Up to date, producing large-area graphene is still a challenge and bottleneck for researchers. The technology about how to conveniently transfer large-area graphene onto other substrates has not been established yet. In this way, it is believed that the present invention will greatly help researchers to be successful with their experiments related to the graphene transferring work.